Basic College Mathematics (9th Edition)

by
Lial, Margaret L.; Salzman, Stanley A.; Hestwood, Diana L.

Published by
Pearson

ISBN 10:
0321825535

ISBN 13:
978-0-32182-553-7

Chapter 5 - Ratio and Proportion - Review Exercises: 44

Answer

$x=105$

Work Step by Step

We can set the cross products of the given proportion equal to each other and then solve for the unknown variable.
$x\times30=45\times70$
$30x=3150$
Divide both sides by 30.
$\frac{30x}{30}=\frac{3150}{30}$
$x=105$